This invention relates to a support structure for a rostrum and particularly, but not exclusively, to a plurality of collapsible and expandable support structures arranged such that a deck can rest upon the supports to create a rostrum. This invention also relates to a rostrum comprising a deck supported by two or more of said support structures.
Support structures are used to provide a secure stand or base on which to locate a raised deck, platform, stage or similar base on which a seating structure can be arranged, thus creating a tiered structure, or auditorium, such as those often found at concerts and outdoor events. Examples of known support structures on which a raised deck may rest can be grouped into different types.
DE 217,697 or U.S. Pat. No. 2,724,150 can represent a first group of known support structures used in configuring a rostrum, wherein a number of supports are arranged to support an inclined deck on which a seating arrangement rests. The rostrum disclosed in DE 217,697 is a complex assembly, comprising a number of individual components, which requires labour intensive manual assembly. Although such rostrum arrangements are advantageous because they are suitable for compact storage and are easily transported, they can be unstable during the assembly process.
A second group of known rostrum arrangements is represented by U.S. Pat. No. 3,400,502, in which a single unit comprising a number of individual nested units can be expanded and retracted. U.S. Pat. No. 3,400,502 discloses a tiered rostrum, in which each tier is formed of a C-shaped support frame and a deck. Each deck is configured upon a common chassis and cooperates with neighbouring tiers to be expandable and retractable from said common chassis.
Rostra created from nested systems, as disclosed in U.S. Pat. No. 3,400,502, overcome the problem of labour intensive assembly by being pre-assembled structures. Being comprised of one single unit, there is an increase in stability during assembly between each of the tiers of the rostrum because each tier is inter-connected to the others within the rostrum structure.
Although nested systems overcome the problem of rostra comprising individual components, nested systems often require a permanently fixed deck to maintain the stability of the frame, to prevent the frame flexing or distorting during extension or retraction. Moreover, a single nested unit requires level and stable ground on which to be installed, otherwise the nested unit is prone to instability when resting upon uneven surfaces. Being formed of one single unit, nested systems are often large, heavy and are unsuitable for compact storage and are difficult to transport.